api: fix typo in <hooks_env/> definition
api: fix typo in <hooks_env/> definition

<hooks_env/> is intended to be a list of name/value pairs rather than
a single name/value pair.

Acked-by: Eoghan Glynn <05a930c6784d3745d96495f57f88bd6091b2dd36@redhat.com>

markmc/rhevm-api,markmc/rhevm-api,markmc/rhevm-api